Not applicable.
Not applicable.
The present invention relates generally to systems for removing heat from a plurality of vertically spaced heat generating electrical components and more particularly to systems for removing heat from cabinets containing a plurality of vertically spaced heat generating electrical components.
In the field of enclosed electrical devices, it is generally required that temperatures inside the enclosure not rise above a level determined by regulating authorities and/or established national or local codes. Since all electrical devices produce heat, some more than others, thermal issues are very important to the electrical enclosure designer. In many instances the physical size of the enclosure must be increased to accommodate the desired number of devices, or reduce the number of electrical devices inside the enclosure in order to maintain a temperature below the maximum allowable rise. Expensive cooling fans and heat sinking apparatus may also be required to obtain the desired combination of enclosure size and number of electrical devices. Therefore, it would be desirable to develop a relatively simple and inexpensive thermal management system that would permit the greatest number of electrical devices to be enclosed in the smallest or most efficient electrical enclosure without exceeding the maximum allowable temperature rise.
In accordance with the present invention, a multi-level thermal management system is provided for cooling a plurality of vertically arranged heat producing electrical devices, including a lower-most electrical device and at least one succeeding upper electrical device. The system includes one wall of an electrical enclosure on which the lower-most electrical device is mounted and at least one mounting surface on which each of the succeeding upper electrical devices are mounted. The mounting surface is arranged such that each succeeding upper electrical device is attached to the mounting surface such that the upper electrical device is positioned generally above and forward with respect to the immediately preceding lower electrical device. The mounting surface, the vertical wall of the electrical enclosure on which the lower electrical component is mounted and two side walls disposed generally perpendicularly between mounting surface and the enclosure wall define an air duct for receiving heated air from all of the preceding lower electrical devices. The air duct segregates heated air from the lower-most and all preceding lower electrical devices from cooler air being drawn through the lower-most and all succeeding upper electrical devices. Each air duct has an air inlet at its lower end and an air outlet at its upper end. The mounting surface and side walls are configured such that the air inlet of the immediately succeeding upper air duct receives the heated air from all preceding lower electrical devices, thus each succeeding upper air duct increases in cross-section. This configuration permits cool air drawn in through appropriately positioned vents in the enclosure to pass over and through the lower-most and all succeeding upper electrical devices and their associated heat sinking arrangements. This configuration provides optimum cooling for the lower most and all succeeding upper electrical devices. A fan can be located adjacent the air outlet of the uppermost air duct to increase the rate of airflow throughout the air duct.